Telegraph system



J. H. BELL. TELEGRAPH SYSTEM. APPLICATION FILED 14m. 4, 1919.

Patented Nov. 16, 1920.

jnvehmr: Jan/7 H. B6

UNITED STATES PATENT OFFICE.

JOHN H. BELL, OF SOUTE ORANGE, NEJV JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEGRAPH SYSTEM.

Application filed January 4, 1918.

T 0 all whom it may concern Be it known that 1, JOHN H. BELL, a citizen of the United States, residing at South Qrange, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Telegraph Systems, of which the following is a full, clear, concise, and exact description.

This invention relatesto systems of communication, and more particularly to sys toms of simultaneous telegraphy and telephony.

The principal object of this invention is to provide an improved organization of apparatus for the reception of telegraphic impulses. F

In applyin the so-called vibrating or self-aiding relay of Gulstad to telegraphic service over circuits which are also used for telephonic communications,inductive effects emanatin from the local or vibratory con trol circuits of such a relay may unfavora affect the telephonic service.

order to overcome such disturbances in the telephonic devices the present invention contemplates an arrangement wherein the electrical and magnetic paths which are associated with the exterior or line circuits of a self-aiding relay will be inductively distinct from the corresponding paths of the local or vibrating circuits of the same relay device.

This invention is illustrated diagrammatically in the accompanying drawing in which only so much of a telegraphic equipment has been shown as will be necessary to a clear understanding of the invention.

In describing this system, an inductively balanced telephone circuit designated by the reference character A terminates in a duplex equipment which comprises bridge or ratio arms B, artificial line devices 0, and an impulse receiving relay D. The relay D is -composed of two sections; the first section E is provided withwindings 1 and 2 which are connected serially between the circuit of one conductor 40 of the metallic telephone line and the artificial line to form a derived circuit with respect to the bridge arm resistances 25 and 26, while windings 3 and 4 of this relay section are similarly connected from the circuit of the other conductor 41 of the telephone circuit. For the second re lay section F, a circuit extends from a grounoed resistance unit 13 through the Specification of Letters Patent.

Patented Nov. 16, 1920.

Serial No. 210,262.

nected to the relay tongue 5 may be considered as extending to a suitable telegraph receiving device, or to circuits suitable for repeating into another telegraphic circuit.

Referring more particularly to the structure of the relay, a suitably pivoted shaft 6 carries, in addition to the relay tongue member 5, armature members 7 and 8 which work in the upper and lower gap-spaces, respectively, present in the magnetic core circuit of the coils 14 of the section E, and armature members 9 and 10 positioned to similarly work in the gap-spaces of the magnetic core energized by the coils 11 and 12 of the section F. Permanent magnets 15 and 16 serve to polarize the armatures of the first and second sections, respectively. For purpose of description it will be assumed that if a positive current were to enter the coil 1 and emerge from the coil 4 the armatures 7 and 8 would bias to the left-hand side, in which position the tongue 5 would engage the positively marked contact stop, while a reversal of such current direction would bias the armatures to the right-hand side, thereby causing the tongue 5 to connect with its negatively marked stop. At the section F the condenser 14 will receive either a positive or a negative charge depending upon whether the tongue 5 is on its positively or its negatively energized contact stop. Since the condenser 14 may be charged only by current routed over the conductor 18 the circuits of the coils 11 and 12 are usually proportioned to provide that the steady current present in the coil 11, by way of the resistance 13 to earth, will be differentially overcome by the current through the coil 12 while it is flowing to charge the condenser 14. At such condenser charging instants, therefore, the coil 12 exerts influence on the associated armatures 9 and Y10 to increase the pressure on the stop ing. immediately on cessation of the condenser charging current through the coil 12, however, the steady current in the coil 11 becomes effective to stress the armatures 9 and 10 toward their opposite position. For example, if the tongue 5 is against its positively energized stop all of the armatures 71() will be to the left-hand side in establishing this position of the tongue, and positive current over the conductor 18, after charging the condenser 14:, will cause the coil 11 to exert a limited force which will have a tendency to move the armatures 9 and 10 to the right-hand position. lVhen the tongue 5 is in connection with its negative stop current of that polarity will act inversely through the coil 11 to stress the armatures-9 and 10 from the right to the left. It will be noted that the resistance 13 and the condenser 14 are each of an adjustable type. Therefore it possible vary the electrical time-constant of tne circuits through the coils 11 and 12 to secure the differential aiding effect already mentioned and also to permit the coil 11 to be influenced by the steady current only to the extent that the normal polarizing stress of all the armatures 71O will be substantially neutralized. During the time the tongue 5 is passing from one to the other of its stops the condenser 14 discharges serially through the windings 11 and 12 and the resistance unit 13. The effect of such discharges are accumulative in the coils 11 and 12 and always in a direction to cause the armatures 9 and 10 to aid the armatures 7 and 8 in moving the tongue 5 to its opposite position.

To make this clear, if the tongue 5 is, say, against its negative stop and an impulse of positive line current enters at the coil 1, the armatures 7 and 8 will be stressed to cause the tongue 5 to separate from its negative stop. The condenser 14 having received a charge from the negative "source at the time the tongue was in contact withthat stop, it follows that so soon as the tongue breaks this connection the condenser will discharge,

thereby causing the coils 11 and 12 to movethe armatures 9 and 10 from the left to the right and will thereby assist the armatures and 8 in moving the tongue 5 across its gap-space to the opposite or positive contact stop. In order that the section E may be inductively distinct both electrically and magnetically from the section F an insert 19 of non-magnetizable material, as brass or aluminum, is placed intermediate the two sections of the relay in establishing mechanical continuity of the shaft Referring more particularly to the o is"- ating features of the system, a telegraph transmitter represented by a key 31 is arranged to alternately establish two oppositely poled batteries 32 and in accumulative relation with the conductors 10 and distant the armatures of the relay 41 of the telephone line A, and at the same time with the artificial line C, it being understood that by means of the adjustable resistances and the adjustable condensers which comprise the artificial line that the electrical characteristics of this line may be calibrated to correspond with the electrical characteristics of the metallic or real line A. A telephone equipment T is connected in bridge on the line conductors 10 and 11, the associated condensers, grounded impedance units and impedance units 29 and 30 restrict the telegraphic currents to their proper paths and prevent other than telephonic currents reaching the-telephone devices.

It will be understood that a distant station (not shown) on the line A. is provided with an equipment identical to the equipment shown in the drawing. Therefore telephonic communication may be carried on between the telephone equipments T and the distant telephone instruments. telegraphic messages may be sent by the transmitting key 31 to be reproduced through a distant line relay correspondin with the relay D, and a distant transmitter equipment co 'respending with the key 31 and aseociat d batteries control, the line relay D in sending telegraphic signals from the distant to the present station.

In describing operations whereby telegraphic signals may be receivedfrom the station a more ready understanding of the relationof the relay D may be had by disregarding, for the moment the pres ence of the transmitting key 31 and its a ciated batteries 32 and Let it therero be assumed that the distant transmitter is operated to connect tie positive side of a line battery with the conductor 1-0 and the negative sine of the same battery with the conductor 41. This positive current arriving over the conductor 10 will traverse the impedance coil 29, a conductor 22. the serially connected windings 1 and 2 of the relay D, a conductor 21, a resistance unit 5350f the artificial line C, a conductor 21, the serially connected windings 3 and a of the relay D, a conductor 23, the impedance coil 30, thence returning over the line conductor a l to the distant station. For purpose of description let it be assumed that at the instant just preceding inception of the positive impulse the tongue 5 of the lay D was biased to engage its negative connected contact stop,

thereby causing the condenser 14 to be negatively charged and also establishing steady current of the same polarity through the coil 11 to set up stress to relieve the major portion of. the polarizing magnetic effect acting to retain the armatures 710 in their right-hand posi tions. This relatively neutral condition of permit an instant response to the positive impulse through the line windings 1-4, and on the instant the tongue 5 separates from its negative stop the condenser 1d discharges through the windings 11 and 12, as already described, thereby causing the armatures 9 and 10 to act through the shaft 6 in aiding the armatures 7 and 8 to move the tongue 5 to its posiively poled stop. On the instant the tongue 5 engages its positive stop the polarizing magnetism in each section of the relay is free to act with any portion of the positive impulse which may still be present in the windings 1-t and also assisted by the condenser charging efiect through the winding 12 in establishing a firm contact between these members. Such instant of firm contact may be considered as the period during which the condenser ll is receiving a charge from the positive source, and on the condenser becoming fully charged the positive current through the coil 11 will become tree to stress the armatures 9 and 10 against the polarizing strains which act to hold the moving members of the relay in their righthand or positive positions, as already mentioned. It will, therefore, be clear that when the distant transmitter establishes a reversal of current with the line conductors so that the conductor 40 becomes negatively energized while the conductor 11 is positively poled, such current through the circuits already traced will set up operations in the relay D which will be identical to but reciprocal of the operations already described in connection with the positive impulse. Suchv current will result in the tongue 5 being moved to its right-hand or negative stop.

Referring now to the operations whereby telegraphic signals may be transmitted to the distant station the battery 32 may supply current over the key 31 to duplex circuit one branch or" which extends over the bridge arm resistance 25, the impedance coil 29, the line conductor aO to the distant station and after passing through the line relay windings and associated circuits at that point this current returns over the line conductor 41, the impedance 30 and the resistance arm 28 to the opposite side of: the battery 32. For the second branch 01": the duplex circuit current passes from the key 31 by way of the bridge resistance 26, the resistance 35 and bridge resistance 27 to the opposite side of the battery 32. Since the artificial line C is in electrical balance with the real line A, as already mentioned, current from the battery 32 by way of the duplex circuits just traced will not disturb anormal condition of zero potential be tween the conductors 21 and 22 or 23 and 24 whereby the windings 1-4 of the home relay D are connected to the system. In transmitting signals by means of the key 31 the batteries 32 and 33 may be alternately connected over the duplex circuits already traced, but due to the balance of these circuits neither of the batteries may disturb the normal position of the home relay. Such changes in polarity over the line A will, however, be effective in operating the line relay at the distant station in a manner similar to that already described for operating the home relay D.

In a more strict description of the changes in current whereby the line relay D may be operated, it will be pointed out that it an impulse of positive current from the distant station A arrives by way of the conductor 10 at a time the key 31 is connected vith the negative battery 32 this battery and the distant battery will form an accumulative couple to increase the strength of current through the line loop 11, without affecting the strength of the current from the battery 32 as present in the artificial line C. Such preponderance of current in the bridge arms 25 and 28 will cause a difference of potential between the CODflUCtOlS 21 and 22 and between the conductors 23 and 24;, thereby setting up currents in the windings 1 and 2, and and l, respectively, which will act to bias the relay D to its positive side. In case the distant key is positioned to send negative current by way of the conductor 10 while the key 31 is in engagement with the negative battery 32, the home and the distant oattery then form a diflerential couple throu the line loop and thereby cause cessat of current through this circuit. Since current condition through the circuits of the artificial line 0 remain undisturbed this electrical condition in the circuits of the real line sets up a difference of potential of inverse polarity to that already described through the windings 1-2 and 31; therefore, the moving parts of the relay D will be biascr to their negative position. Results similar to the responses of the relay D as described will be had whether the key 31 be con nected with the battery 32 or with the but tery 33. Such changes of current condition are in accordance with the usual phenomenon which characterizes the working of duplex telegraphs.

A further advantage or" the relay apparatus employed in the present invention may be mentioned as a bettering of the operating efficiency or the relay. Aside from the obvious advantage in the cubical space as the volume of the windings as compared with a compound-wound relay, the absence of any transformer effect between the ex teriorly connected windings 1- l and the locally connected windings 11 and 12 materially increases the eiiiciency or sensitive ness of the device. In compound-wound relays the inductive action is invariably differential with respect to the inducing current; therefore, it will be obvious that the multiple-section self-aiding relay above de scribed may be readily applied in any situation that may require a supersensitive re-- lay.

lVhat is claimed is:

l. A telegraph receiving system comprising' in combination with a line circuit, a plurality of electromagnets, armatures therefor, a common suspension means of non-magnetic material connecting said armatures together, one of said electromagnets being responsive to signals in said line circuit to cause an initial movement of said armatures and a local circuit including another of said electromagnets and controlled by said initial movement to aid said line signals in moving said armatures.

2. A telegraph receiving system compris.-

ing a plurality of polarized electromagnetic structures, an armature'indlvldual to each of said structures, pivotally supported nonmagnetizable means for joining said armatures, a line circuit through which one of said electroresponsive structures is energized to cause an initial movement of said armatures, a local circuit including contacts controlled by said movement for energizing another of said electroresponsive structures to aid in the movement of said armatures.

3. A telegraph receiving system comprising a polarized relay having an armature responsive to telegraphic signals, a polarized electromagnet having its armature connected to the armature of said polarized relay by a common pivotal support but magnetically separated therefrom, a local circuit including adjustable inductance and capacity and means controlled by aninitial movement of the armature of said polarizedrelay to energize said local circuit and said polarized electromagnet to aid in the movement of the armature of said polarized relay.

4. A telegraph receiving system comprising a polarizedrelay responsive to signaling impulses, a polarized electromagnet having its armature fixed to polarized relay, a pivotal support common to said armatures, a local circuit controlled by said polarized relayto render said polarized electromagnet effective to aid in the operation of said polarized relay, and means includedin said local circuit to vary the time constant of operation of said polarized electromagnet to correspond to the time constant of operation of said polarized relay.

In a telegraph system, an electrically balanced telephone circuit, an artificial line having electrical characteristics corresponding with said telephone circuit, a relay, ratio resistances connected intermediate each conductor of said metallic circuit and said artificial line, impulse transmitting means bridged on said circuits at a point intermediate said ratio: resistances, a plurality of windings for said relay respectively bridged on the ratio resistances of each si'de'of said metallic circuit torender the'relay unresponsive to impulses from said transmitter, an electromagnet controlled by said relay. and means controlled by said electromagnet for aiding in the operation of said relay.

6. Ina system of simultaneous telegraphy and telephony, an electrically balanced telephone circuit, an artificial line, a relay, a plurality of windings for said relay respectively connected intermediate each conductor of said metallic circuit and said artificial line, transmitter for establishing impulses in accumulative relation over said'metallic circuit to operate said relay, an electromagnet controlled'by saidrelay inductively insulated bothelectrically and-magnetically from said relay, and means controlled by said electromagnet to aid in the operation of said relay.

In witness whereof I hereunto subscribe n1y7name this 29th day of December, A. D. 191 l V JOHN H. BELL.

the armature of said- 

